1. Field of the Invention
This invention relates to a method and apparatus for bending tubing, such as electrical conduit.
2. Discussion of Related Art
Conventional conduit benders are typically used in the field at a commercial, residential or industrial construction site to bend conduit pipe or electrical metallic tubing (EMT). Power benders are typically used to bend EMT having a diameter greater than about 1 inch. Even though power benders can be used for smaller diameter tubing, hand benders having a shoe and a handle are used to roll the conduit between the hand bender and typically a ground or floor surface. Many commercial, residential and industrial construction sites require hundreds, some even thousands, of custom bent EMT pieces which are typically joined together to form a structured EMT network, sometimes having an elaborate configuration, through which wire is routed. Many EMT pieces require multiple bends. With so many bends it is often time and cost inefficient to use a power bender.
EMT pieces often require several bends that are made sequentially in the field, by measuring and forming a first bend and then holding the EMT piece in place to measure or estimate the size and location of the next sequential bend. Many EMT runs are positioned or located in an area that is accessed only by scaffolding, a lift or a ladder, which makes the installation task inefficient, difficult and impractical because of continually climbing up and down, to and from, the elevated area to access a hand bender or power bender which is located on a ground surface or on a different floor level.
Most EMT at a residential site has a diameter of one inch or less, and typically has a diameter of ½ inch to ¾ inch. Most EMT at a residential construction site is bent or formed by hand, in the field or at the job site, by an electrician using a conventional hand bender. A bending shoe of the hand bender often has a groove that matches an outer diameter of the EMT, and also supports an inside radius and outer walls of the EMT, during a bend process. Hand benders are used to roll the EMT between the hand tool and the floor surface, to gradually increase a radius of the bend. Many conventional hand benders have a hook at one end of the shoe, for gripping the EMT and pulling the EMT away from the ground surface or the floor, to form a bend.
The EMT is positioned within or rides within the groove formed by the shoe. The shoe is rotated or moved with respect to the floor or the ground surface, about a periphery of the shoe. Because residential sites and even many commercial and industrial sites require so much conduit less than one inch in diameter, electricians exert undue stresses and forces on their backs and other body parts, particularly when bending over multiple times, even hundreds of times per day, to first lift the EMT from the ground surface or the floor, carry the EMT to a bender, and then bend the EMT. In a typical work day, an electrician can be required to bend conduit as many as 300 to 500 times.
Not only does the manual bending process exert undue stresses on the body, but also operating the hand bender at an elevated location, such as on scaffolding, a ladder or a lift, is dangerous and can cause a safety hazzard.
It is apparent that there is a need for a bending apparatus that can stand on a ground surface, can be mounted upon scaffolding or a wall, or can be mounted upon any other similar construction or other structure.
There is a need for a bending apparatus that does not require the user to operate a bending tool against a floor surface or a ground surface.
There is a need for a bending apparatus that has a simple, rugged construction that is lightweight and portable, and that is relatively inexpensive.
There is a need for a bending apparatus that conveniently accommodates a conventional hand bender, particularly without the need for an electrician or other user to bend over or stoop and use the floor or ground to bend the EMT.